JP6766278B1 - Suspension control device and suspension device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize control of a suspension capable of synchronizing a roll and a pitch of a vehicle. SOLUTION: In a suspension control device for controlling a damping force of a suspension, a target pitch angle calculation unit (891) for calculating a target pitch angle with reference to a roll angle signal and a control of the damping force of the suspension are referred to. It is provided with a target control amount calculation unit (894) that calculates a roll posture target control amount with reference to a steering torque signal and a target pitch angle. [Selection diagram] Fig. 4

Description

The present invention relates to a suspension control device and a suspension device.

In the control of the traveling state of the vehicle, from the viewpoint of enhancing the safety in the traveling of the vehicle, a control for synchronizing the roll and the pitch as the vehicle motion is disclosed by using the technique of controlling the brake or the suspension. (See, for example, Patent Document 1).

U.S. Patent Application Publication No. 2004/0024504

However, the above-mentioned patent document does not disclose a specific control method for the control for synchronizing the roll and the pitch.

One aspect of the present invention is to realize control of a suspension capable of synchronizing the roll and pitch of a vehicle.

In order to solve the above problems, the suspension control device according to one aspect of the present invention is a suspension control device that controls the damping force of the suspension, and is a target for calculating a target pitch angle with reference to a roll angle signal. It includes a pitch angle calculation unit and a target control amount calculation unit that calculates a target control amount referred to when controlling the damping force of the suspension by referring to the steering torque signal and the target pitch angle. ..

Further, in order to solve the above problems, the suspension device according to one aspect of the present invention is a suspension device including a suspension and a control unit for controlling the damping force of the suspension, and the control unit is a roll. The target pitch angle calculation unit that calculates the target pitch angle with reference to the angle signal, and the target control amount referred to when controlling the damping force of the suspension, refer to the steering torque signal and the target pitch angle. It is equipped with a target control amount calculation unit for calculating.

According to one aspect of the present invention, it is possible to synchronize the roll and pitch of the vehicle by controlling the suspension.

It is a figure which shows typically an example of the structure of the vehicle in Embodiment 1 of this invention. It is a block diagram which shows an example of the functional structure of the suspension control part in Embodiment 1 of this invention. It is a block diagram which shows an example of the functional structure of the roll posture control part in Embodiment 1 of this invention. It is a block diagram which shows an example of the functional structure of the roll posture target control amount in Embodiment 1 of this invention. It is a block diagram which shows an example of the functional structure of the target pitch angle calculation part in Embodiment 1 of this invention. It is a figure which shows the example which the time difference between the peak of a roll angle and a pitch angle of a vehicle is small. It is a figure which shows the example which the time difference between a peak of a roll angle and a pitch angle of a vehicle is large. It is a block diagram which shows an example of the functional structure of the target pitch angle calculation part in Embodiment 2 of this invention. It is a block diagram which shows an example of the functional structure of the roll posture target control amount in Embodiment 3 of this invention.

The present inventors have diligently studied the control of the suspension that enables the roll and pitch of the vehicle to be synchronized. As a result, they have found that it is possible to enhance the sense of unity with the vehicle that the driver of the vehicle feels by controlling the suspension so as to enable the roll and pitch of the vehicle to be synchronized.

[Embodiment 1]
Hereinafter, one embodiment of the present invention will be described in detail. First, a vehicle in which the suspension device and the suspension control device according to the embodiment of the present invention are adopted will be described. In the present specification, the expression "refer to" may include meanings such as "using", "considering", and "depending on". Further, specific examples of the "control amount" in the present specification include a current value, a duty ratio, an attenuation rate, an attenuation ratio, and the like.

[Vehicle configuration]
FIG. 1 is a diagram schematically showing an example of a vehicle 900 configuration according to the present embodiment. As shown in FIG. 1, the vehicle 900 includes a suspension device (suspension) 100, a vehicle body 200, wheels 300, tires 310, steering member 410, steering shaft 420, torque sensor 430, steering angle sensor 440, torque application unit 460, and rack. It includes a pinion mechanism 470, a rack shaft 480, an engine 500, an ECU (Electronic Control Unit) (control device, control unit) 600, a power generation device 700, and a battery 800. Here, the suspension device 100 and the ECU 600 constitute the suspension device according to the present embodiment.

The wheel 300 on which the tire 310 is mounted is suspended from the vehicle body 200 by the suspension device 100. Since the vehicle 900 is a four-wheeled vehicle, the suspension device 100, the wheels 300, and the tires 310 are provided on each of the four wheels.

The tires and wheels of the left front wheel, the right front wheel, the left rear wheel and the right rear wheel are the tire 310A and the wheel 300A, the tire 310B and the wheel 300B, the tire 310C and the wheel 300C, and the tire 310D and the wheel, respectively. Also called 300D. Hereinafter, similarly, the configurations attached to the left front wheel, the right front wheel, the left rear wheel, and the right rear wheel are represented by adding the reference numerals “A”, “B”, “C”, and “D”, respectively. There is.

The suspension device 100 includes a hydraulic shock absorber (absorber), an upper arm, and a lower arm. Further, as an example, the hydraulic shock absorber includes a solenoid valve which is a solenoid valve for adjusting the damping force generated by the hydraulic shock absorber. However, this does not limit the present embodiment, and the hydraulic shock absorber may use a solenoid valve other than the solenoid valve as the solenoid valve for adjusting the damping force. For example, the solenoid valve may be provided with a solenoid valve using an electromagnetic fluid (magnetic fluid).

A power generation device 700 is attached to the engine 500, and the electric power generated by the power generation device 700 is stored in the battery 800.

The steering member 410 operated by the driver is connected to one end of the steering shaft 420 so as to be able to transmit torque, and the other end of the steering shaft 420 is connected to the rack and pinion mechanism 470.

The rack and pinion mechanism 470 is a mechanism for converting the rotation of the steering shaft 420 around the axis into a displacement of the rack shaft 480 along the axial direction. When the rack shaft 480 is displaced in the axial direction, the wheels 300A and the wheels 300B are steered via the tie rod and the knuckle arm.

The torque sensor 430 detects the steering torque applied to the steering shaft 420, in other words, the steering torque applied to the steering member 410, and provides the ECU 600 with a torque sensor signal indicating the detection result. More specifically, the torque sensor 430 detects the twist of the torsion bar built in the steering shaft 420 and outputs the detection result as a torque sensor signal. As the torque sensor 430, a well-known sensor such as a Hall IC, an MR element, or a magnetostrictive torque sensor may be used.

The steering angle sensor 440 detects the steering angle of the steering member 410 and provides the detection result to the ECU 600.

The torque application unit 460 applies an assist torque or a reaction force torque according to the steering control amount supplied from the ECU 600 to the steering shaft 420. The torque application unit 460 includes a motor that generates an assist torque or a reaction force torque according to the steering control amount, and a torque transmission mechanism that transmits the torque generated by the motor to the steering shaft 420.

In the above description, "connecting so that torque can be transmitted" means that the members are connected so that the rotation of one member causes the rotation of the other member. For example, when one member and the other member are integrally molded, when the other member is directly or indirectly fixed to one member, and when one member and the other member are fixed. At least the case where the members are connected so as to be interlocked with each other via a joint member or the like is included.

Further, in the above example, a steering device in which the steering member 410 to the rack shaft 480 are always mechanically connected is given as an example, but this is not limited to this embodiment. For example, the steering device according to the present embodiment may be, for example, a steering device of a steer-by-wire system. The matters described below can also be applied to the steering device of the steer-by-wire system.

The ECU 600 collectively controls various electronic devices included in the vehicle 900. For example, the ECU 600 controls the magnitude of the assist torque or reaction force torque applied to the steering shaft 420 by adjusting the steering control amount supplied to the torque application unit 460.

Further, the ECU 600 controls the opening and closing of the solenoid valve by supplying a suspension control amount to the solenoid valve included in the hydraulic shock absorber included in the suspension device 100. In order to enable this control, a power line for supplying drive power from the ECU 600 to the solenoid valve is arranged.

Further, the vehicle 900 is provided for each wheel 300, and has a wheel speed sensor 320 that detects the wheel speed of each wheel 300, a lateral G sensor 330 that detects the lateral acceleration of the vehicle 900, and detects the acceleration in the front-rear direction of the vehicle 900. The front and rear G sensor 340, the yaw rate sensor 350 for detecting the yaw rate of the vehicle 900, the engine torque sensor 510 for detecting the torque generated by the engine 500, the engine rotation speed sensor 520 for detecting the rotation speed of the engine 500, and the braking device. A brake pressure sensor 530 that detects the pressure applied to the brake liquid is provided. The detection results by these various sensors are supplied to the ECU 600.

Although not shown, the vehicle 900 includes ABS (Antilock Brake System), which is a system for preventing wheel lock during braking, TCS (Traction Control System), which suppresses wheel idling during acceleration, and the like. It is equipped with a VSA (Vehicle Stability Assist) controllable brake device, which is a vehicle behavior stabilization control system equipped with an automatic braking function for yaw moment control during turning or a brake assist function.

Here, ABS, TCS, and VSA compare the wheel speed determined according to the estimated vehicle body speed with the wheel speed detected by the wheel speed sensor 320, and the values of these two wheel speeds are predetermined values. If the above differences occur, it is determined that the vehicle is in a slip state. Through such processing, ABS, TCS, and VSA aim to stabilize the behavior of the vehicle 900 by performing optimum brake control or traction control according to the traveling state of the vehicle 900.

Further, the supply of the detection results by the various sensors described above to the ECU 600 and the transmission of the control signal from the ECU 600 to each part are performed via the CAN (Controller Area Network) 370.

[Suspension control unit]
Hereinafter, the ECU 600 will be specifically described by changing the reference drawing. The ECU 600 includes a suspension control unit 650. The ECU 600 is one aspect of the suspension control device of the present embodiment.

The suspension control unit 650 refers to the detection results of various sensors included in the CAN 370, and determines the magnitude of the suspension control amount supplied to the solenoid valve 105 included in the hydraulic shock absorber included in the suspension device 100. The process of "determining the magnitude of the control amount" includes the case where the magnitude of the control amount is set to zero, that is, the control amount is not supplied.

Subsequently, the suspension control unit 650 will be described more specifically with reference to FIG. FIG. 2 is a block diagram showing an example of the functional configuration of the suspension control unit 650.

As shown in FIG. 2, the suspension control unit 650 includes a CAN input unit 660, a vehicle state estimation unit 670, a steering stability / riding comfort control unit 680, and a control amount selection unit 690.

The CAN input unit 660 acquires various signals via the CAN 370. For example, as shown in FIG. 2, the CAN input unit 660 acquires the following signals (parentheses indicate the acquisition source).
・ Wheel speed of 4 wheels (wheel speed sensor 320A to D)
・ Yaw rate (yaw rate sensor 350)
・ Front and rear G (front and rear G sensor 340)
・ Horizontal G (horizontal G sensor 330)
・ Brake pressure (brake pressure sensor 530)
・ Engine torque (engine torque sensor 510)
-Engine speed (engine speed sensor 520)
・ Rudder angle (rudder angle sensor 440)
・ Steering torque (torque sensor 430)

The vehicle state estimation unit 670 estimates the state of the vehicle 900 with reference to various signals acquired by the CAN input unit 660. As an estimation result, the vehicle state estimation unit 670 outputs the spring speed of the four wheels, the stroke speed of the four wheels, the pitch rate, the roll rate, the roll rate during steering, and the pitch rate during acceleration / deceleration.

As shown in FIG. 2, the vehicle state estimation unit 670 includes an acceleration / deceleration / steering correction amount calculation unit 671, an acceleration / deceleration / steering pitch / roll rate calculation unit 673, and a state estimation single-wheel model application unit 674. It has.

Acceleration / deceleration / steering correction amount calculation unit 671 refers to the yaw rate, front / rear G, wheel speeds of four wheels, brake pressure, engine torque, and engine speed, and adjusts the vehicle body front / rear speed, inner / outer wheel difference ratio, and adjustment. The gain is calculated, and the calculation result is supplied to the state estimation single-wheel model application unit 674.

The acceleration / deceleration / steering pitch / roll rate calculation unit 673 calculates the steering roll rate and the acceleration / deceleration pitch rate with reference to the front-rear G and the lateral G. The calculation result is supplied to the steering stability / riding comfort control unit 680.

The acceleration / deceleration / steering pitch / roll rate calculation unit 673 may be configured to further refer to the suspension control amount output by the control amount selection unit 690. Further, the roll rate value may be configured to take "0" as a reference value when the inclination of the vehicle 900 does not change for a predetermined minute time, and may represent the roll rate as a deviation from the reference value. .. Further, the acceleration / deceleration / steering pitch / roll rate calculation unit 673 may provide a dead zone of about ± 0.5 in the steering roll rate. Here, the reference numerals are, for example, "+" on the left side of the vehicle 900 and "-" on the right side.

The state estimation single-wheel model application unit 674 applies the state estimation single-wheel model to each wheel with reference to the calculation result by the acceleration / deceleration / steering correction amount calculation unit 671, and the sprung speed of the four wheels. Calculate the stroke speed, pitch rate, and roll rate of the four wheels. The calculation result is supplied to the steering stability / riding comfort control unit 680.

The steering stability / riding comfort control unit 680 includes a skyhook control unit 681, a roll attitude control unit 682, a pitch attitude control unit 683, and an unsprung control unit 684.

The skyhook control unit 681 performs ride comfort control (vibration control control) that suppresses the shaking of the vehicle when overcoming the unevenness of the road surface and enhances the ride comfort. As an example, the skyhook control unit 681 determines the skyhook target control amount with reference to the spring speed of the four wheels, the stroke speed of the four wheels, the pitch rate, and the roll rate, and determines the result as the control amount selection unit. Supply to 690.

As a more specific example, the skyhook control unit 681 sets the damping force base value by referring to the spring-damping force map based on the spring velocity. Further, the skyhook control unit 681 calculates the skyhook target damping force by multiplying the set damping force base value by the skyhook gain. Then, the skyhook target control amount is determined based on the skyhook target damping force and the stroke speed.

The roll attitude control unit 682 performs roll attitude control by calculating the roll attitude target control amount with reference to the roll rate at the time of steering, the steering angle signal indicating the steering angle, and the steering torque signal indicating the steering torque. The calculated roll posture target control amount is supplied to the control amount selection unit 690. The specific configuration of the roll attitude control unit 682 will be described later.

The pitch attitude control unit 683 performs pitch control with reference to the pitch rate during acceleration / deceleration, determines a pitch target control amount, and supplies the result to the control amount selection unit 690.

The unsprung control unit 684 controls the unsprung vibration of the vehicle 900 with reference to the wheel speeds of the four wheels, and determines the unsprung vibration control control target control amount. The determination result is supplied to the control amount selection unit 690.

The control amount selection unit 690 selects the target control amount having the largest value among the skyhook target control amount, the roll attitude target control amount, the pitch target control amount, and the unsprung vibration suppression control target control amount, and the suspension control amount. Output as.

[Roll posture control unit]
Hereinafter, the roll attitude control unit 682 will be described more specifically with reference to FIG. FIG. 3 is a block diagram showing an example of the functional configuration of the roll attitude control unit 682 according to the present embodiment. The roll attitude control unit 682 calculates the roll attitude target control amount with reference to the roll angle signal, the actual pitch angle signal, the steering angle signal, the steering angle speed signal, the roll rate signal, and the steering torque signal.

Here, as the roll angle signal referred to by the roll attitude control unit 682, for example, the vehicle 900 may be configured to include a roll angle sensor, and the output from the roll angle sensor may be used as the roll angle signal. , Not limited to this. For example, the roll rate calculated by the vehicle state estimation unit 670 may be integrated by the vehicle state estimation unit 670, and the roll angle obtained by the integration may be used as the roll angle signal.

Further, as the actual pitch angle signal referred to by the roll attitude control unit 682, for example, the vehicle 900 may be configured to include a pitch angle sensor, and the output from the pitch angle sensor may be used as the pitch angle signal. , Not limited to this. For example, the pitch rate calculated by the vehicle state estimation unit 670 may be integrated by the vehicle state estimation unit 670, and the pitch angle obtained by the integration may be used as the actual pitch angle signal.

Further, as the steering angle speed signal referred to by the roll attitude control unit 682, the steering angle signal output by the CAN input unit 660 is differentiated by, for example, the steering stability / riding comfort control unit 680, and is obtained by the differentiation. The steering angle speed may be used as the steering angle speed signal.

Here, the roll posture target control amount can be a target control amount that is a candidate for the suspension control amount, in other words, a target control amount that is referred to when controlling the damping force of the suspension. For example, the roll attitude target control amount calculated by the roll attitude control unit 682 is the suspension control amount when selected by the control amount selection unit 690. Therefore, it can be expressed that the roll attitude control unit 682 calculates the suspension control amount.

As shown in FIG. 3, the roll attitude control unit 682 includes a steering angle target control amount calculation unit 81, a steering angle speed target control amount calculation unit 82, a roll rate target control amount calculation unit 83, and a steering torque target control amount calculation unit 84. , Steering torque speed calculation unit 85, steering torque speed target control amount calculation unit 86, steering torque-derived target control amount selection unit 87, roll posture-derived target control amount selection unit 88, and roll attitude target control amount calculation unit 89. There is.

The steering angle target control amount calculation unit 81 calculates the steering angle target control amount with reference to the steering angle indicated by the steering angle signal. The steering angle speed target control amount calculation unit 82 calculates the steering angle speed target control amount with reference to the steering angle speed signal. The steering angle target control amount calculation unit 81 and the steering angle speed target control amount calculation unit 82 both refer to the steering angle signal to suppress the roll of the vehicle 900, and the target is such that the attitude of the vehicle 900 becomes closer to flat. Calculate the control amount.

The roll rate target control amount calculation unit 83 calculates the roll rate target control amount with reference to the steering roll rate supplied from the acceleration / deceleration / steering pitch / roll rate calculation unit 673.

The steering torque target control amount calculation unit 84 calculates the steering torque target control amount with reference to the steering torque signal indicated by the steering torque signal. The steering torque speed calculation unit 85 calculates the steering torque speed by referring to the time change of the steering torque indicated by the steering torque signal. The steering torque speed target control amount calculation unit 86 calculates the steering torque speed target control amount for each of the four wheels of the vehicle 900 with reference to the steering torque speed calculated by the steering torque speed calculation unit 85.

In this way, the steering torque target control amount calculation unit 84 and the steering torque speed target control amount calculation unit 86 both directly or indirectly refer to the steering torque signal to suppress the roll of the vehicle 900, and the posture of the vehicle 900 is changed. Calculate the target control amount that approaches flatter.

The steering torque-derived target control amount selection unit 87 selects a target control amount having a higher value from the steering torque target control amount and the steering torque speed target control amount as the steering torque-derived target control amount.

The roll posture-derived target control amount selection unit 88 has a higher value among the steering angle target control amount, the steering angle speed target control amount, the roll rate target control amount, and the steering torque-derived target control amount. Is selected as the target control amount derived from the roll posture. In the present embodiment, in the calculation of the suspension control amount, the control until the roll posture-derived target control amount selection unit 88 selects the roll posture-derived target control amount is also referred to as “steering torque response control”.

(Roll posture target control amount calculation unit)
FIG. 4 is a block diagram showing an example of the functional configuration of the roll posture target control amount calculation unit 89 in the present embodiment. As shown in FIG. 4, the roll posture target control amount calculation unit 89 includes a target pitch angle calculation unit 891, a subtraction unit 892, a pitch moment calculation unit 893, and a target control amount calculation unit 894.

The target pitch angle calculation unit 891 calculates the target pitch angle with reference to the roll angle signal. FIG. 5 is a block diagram showing an example of the functional configuration of the target pitch angle calculation unit in the present embodiment. For example, the target pitch angle calculation unit 891 includes an absolute value calculation unit 91 and a gain multiplication unit 92, as shown in FIG. The absolute value calculation unit 91 calculates the absolute value of the roll angle indicated by the roll angle signal and supplies it to the gain multiplication unit 92. The gain multiplication unit 92 calculates the target pitch angle by multiplying the absolute value of the roll angle supplied from the absolute value calculation unit 91 by the gain.

As shown in FIG. 4, the roll posture target control amount calculation unit 89 further refers to the actual pitch angle to calculate the target control amount. More specifically, the roll posture target control amount calculation unit 89 calculates the target control amount according to the difference between the target pitch angle and the actual pitch angle.

The subtraction unit 892 calculates the difference obtained by subtracting the actual pitch angle from the target pitch angle calculated by the target pitch angle calculation unit 891.

The pitch moment calculation unit 893 calculates the pitch moment of the vehicle 900 according to the difference in pitch angles calculated by the subtraction unit 892. By calculating the pitch moment of the vehicle 900 according to the difference in pitch angle, a more suitable pitch moment can be calculated from the viewpoint of attitude control as compared with the case where the pitch moment is calculated without referring to the actual pitch angle. Can be done.

The target control amount calculation unit 894 calculates the target control amount with reference to the pitch moment calculated by the pitch moment calculation unit 893 and the roll posture-derived target control amount selected by the roll posture-derived target control amount selection unit 88. The target control amount obtained by this calculation is the roll attitude target control amount described above, and is an output value of the roll attitude control unit 682 described above.

Here, when the target control amount derived from the roll posture is the target control amount derived from the steering torque, the target control amount calculation unit 894 receives and accepts, for example, the target control amount derived from the steering torque as the target control amount derived from the roll posture. The roll attitude target control amount is calculated by adding the pitch moment to the steering torque-derived target control amount.

As described above, the target control amount derived from the steering torque is a control amount obtained with reference to the steering torque signal. Further, the roll posture target control amount is a target control amount referred to when controlling the damping force of the suspension. In this way, the target control amount calculation unit 894 calculates the target control amount with reference to the steering torque signal and the target pitch angle. For example, the target control amount calculation unit 894 can calculate the roll attitude target control amount by referring to the steering torque-derived target control amount obtained by referring to the steering torque signal and the target pitch angle.

In the present embodiment, the roll posture-derived target control amount is the steering torque-derived target control amount, and the control for calculating the roll posture target control amount with reference to the roll posture-derived target control amount and the pitch moment is "steering." Also called "torque reference control".

Here, the suspension control according to the present embodiment will be described more specifically from the steering of the driver.

First, when the driver turns the steering member 410, the steering torque is generated and the steering torque signal is generated by the turning operation of the steering member 410 by the driver. The wheels 300A and 300B are steered so as to have a steering angle corresponding to the generated steering torque signal, and the vehicle 900 turns according to the steering angle.

When the vehicle 900 is turning, a damping force is generated according to the displacement speed of the absorbers (front wheel side absorber and rear wheel side absorber) due to the roll motion, and according to the difference between the damping force on the extension side and the damping force on the contraction side. A force is generated to push down the axle. In addition, a pitch moment is generated due to the difference in damping force between the front and rear wheels. Therefore, when the vehicle 900 turns, a motion in which a roll motion and a pitch motion are combined is generated in the vehicle 900. As described above, the motion of the vehicle 900 is detected as various state quantities by the various sensors described above. The detection result is input to the CAN input unit 660 as described above, and is used for controlling the operation of the suspension device 100 described above.

In the present embodiment, control for improving the turning sensation can be performed by referring to the roll angle and the pitch angle. For example, the suspension is controlled so that the time difference between the peak of the pitch angle and the peak of the roll angle in the vehicle 900 becomes smaller. By this control, the driver of the vehicle 900 can feel a good turning sensation.

More specifically, the target control amount calculation unit 894 refers to the roll angle of the vehicle 900 and the pitch moment calculated by the pitch moment calculation unit 893. Then, the roll posture target control amount for reducing the difference between the phase of the roll angle in the vehicle 900 and the phase of the pitch angle obtained from the pitch moment is calculated.

Here, in the calculation of the roll posture target control amount by the target control amount calculation unit 894, the difference between the phase of the roll angle and the phase of the pitch angle is within a range sufficiently small for the driver to obtain a good turning feeling. It can be set as appropriate. From the viewpoint of obtaining a good turning sensation for the driver, the difference is preferably as small as possible, for example, preferably 1/4 cycle or less, more preferably 1/8 cycle or less, and zero. Most preferred. The "cycle" may be a roll angle cycle or a pitch angle cycle, but from the above viewpoint, it may be a smaller cycle of the roll angle cycle and the pitch angle cycle. Is preferable.

FIG. 6 is a diagram showing an example in which the time difference between the peaks of the roll angle and the pitch angle of the vehicle 900 is small. With the phase difference shown in FIG. 6, the driver of the vehicle 900 can generally obtain a good turning sensation. The time difference between peaks is the time difference between the peak of the roll angle and the peak of the pitch angle closest to each other on the time axis. The time difference is called a phase difference, and when the time difference is zero, the roll angle and the pitch angle are said to be synchronized.

The target control amount calculation unit 894 calculates a roll attitude target control amount that sufficiently reduces the difference between the phase of the roll angle and the phase of the pitch angle. Then, the roll posture target control amount is calculated with reference to the calculated roll posture target control amount, based on the roll posture-derived target control amount selected by the roll posture-derived target control amount selection unit 88. For example, the target control amount calculation unit 894 calculates the roll posture target control amount by adding the roll posture target control amount to the roll posture-derived target control amount selected by the roll posture-derived target control amount selection unit 88. .. The above-mentioned control for reducing the difference between the phase of the roll angle and the phase of the pitch angle based on the above-mentioned pitch moment is also referred to as "phase difference reference control".

On the other hand, if the time difference between the peaks of the roll angle and the pitch angle of the vehicle 900 is large, the driver of the vehicle 900 generally cannot obtain a good turning feeling. FIG. 7 is a diagram showing an example in which the time difference between the peaks of the roll angle and the pitch angle of the vehicle 900 is large. With the phase difference shown in FIG. 7, the driver of the vehicle 900 may feel some discomfort between, for example, the steering performed by himself / herself and the turning sensation obtained thereby. The roll attitude target control amount calculated based on the difference between the roll angle phase and the pitch angle phase is added to the roll attitude-derived target control amount selected by the roll attitude-derived target control amount selection unit 88. However, the driver of the vehicle 900 cannot obtain a good turning sensation.

(Effect of steering torque response control)
In the present embodiment, the steering torque-derived target control amount selection unit 87 selects a target control amount having a higher value from the steering torque target control amount and the steering torque speed target control amount as the steering torque-derived target control amount. To do. In general, the torque speed, which is a time change of the torque, tends to rise faster than the torque indicated by the steering torque signal. Similarly, the steering angle speed, which is a time change of the steering angle, tends to rise faster than the steering angle indicated by the steering angle signal. Then, the roll posture-derived target control amount selection unit 88 has a higher value among the steering angle target control amount, the steering angle speed target control amount, the roll rate target control amount, and the steering torque-derived target control amount. The control amount is selected as the target control amount derived from the roll posture. Therefore, according to the present embodiment, more appropriate suspension control that responds swiftly to changes in steering conditions can be performed.

Further, since the roll attitude control unit 682 calculates the target control amount derived from the roll attitude, which is a candidate for the suspension control amount, with reference to the steering torque signal and the steering angle signal, the control of the damping force of the suspension is controlled by the steering status. It can be done appropriately according to.

Further, the roll attitude control unit 682 can calculate the target control amount derived from the steering torque so that the damping force of the suspension on the side opposite to the steering direction becomes large. In this case, it is possible to realize a good ride comfort and stability of the vehicle 900 according to the steering condition.

(Effect of phase difference reference control)
When the vehicle 900 turns, a motion in which a roll motion and a pitch motion are combined is generated in the vehicle 900. In this case, the gain characteristic of the pitch angle with respect to the roll angle can be set by appropriately setting the difference in damping force between the left and right and the front and rear. Further, by appropriately setting the roll rate and the absorber displacement speed, the phase difference of the pitch angle with respect to the roll angle can be set. Further, by optimally setting or controlling the phases of these movements, the driver's turning sensation can be improved, and as a result, the behavior of the vehicle 900 by the driver can be easily recognized. The turning sensation is a sense of change in the behavior of the vehicle with the five senses of the driver.

According to the present embodiment, the damping characteristics of the front wheel side absorber and the rear wheel side absorber are set so that the phase difference between the roll angle period and the pitch angle period becomes smaller. As a result, the phase of the combined motion of the roll motion and the pitch motion in the vehicle 900 is optimized, and it becomes possible to realize the vehicle behavior with a sense of unity between the roll motion and the pitch motion in the transient motion. .. Therefore, the driving burden on the driver can be reduced.

(Effect of steering torque reference control)
As described above, when the driver steers the vehicle 900 with the steering member 410, steering torque is generated at the start of steering, and a steering torque signal is generated. The generated steering torque signal is referred to by the roll attitude target control amount calculation unit 89 as the steering torque-derived target control amount. The target control amount calculation unit 894 calculates the roll posture target control amount with reference to the roll posture-derived target control amount and the pitch moment selected by the roll posture-derived target control amount selection unit 88.

According to the present embodiment, the roll posture target control amount, which is the target control amount for enhancing the driver's turning sensation, is prepared when the steering torque signal is detected. Therefore, in the present embodiment, the roll posture target control amount is prepared and used for suspension control even before the driver actually starts steering with the steering member 410 and the vehicle 900 makes a turning motion. Then, as the steering amount of the steering member 410 increases, the control effect of the suspension by the roll posture target control amount becomes stronger.

The roll attitude target control amount increases from the time when the steering torque is generated. As described above, in the present embodiment, the suspension is controlled so as to enhance the driver's turning sensation from the start of turning the steering member 410. Therefore, the driver's sense of turning is enhanced from the beginning of the steering operation of the steering member 410, and the sense of unity with the vehicle 900 that the driver feels is further enhanced.

On the other hand, control that enhances the driver's turning sensation according to the state of the vehicle 900, as in the case where the occurrence of the roll motion of the vehicle 900 due to the vehicle 900 starting the turning motion is detected. When the above is performed, the suspension control by the roll posture target control amount substantially acts after a predetermined time has elapsed from the driver starting the steering operation of the steering member 410. Therefore, in the case of performing control to enhance the driver's turning sensation according to the state of the vehicle 900, the driver's turning sensation is improved after the turning operation of the steering member 410 begins to be substantially reflected in the behavior of the vehicle 900. Is enhanced. Suspension control that enhances the turning sensation is not reflected between the turning operation and the improvement of the turning sensation, and during this period, the sense of unity with the vehicle 900 that the driver feels cannot be enhanced.

As is clear from the above description, it can be said that this embodiment is a mode in which the roll posture target control amount is always calculated and another target control amount derived from the steering torque is always added.

Generally, after the steering torque is input, a yaw motion is generated in the vehicle, and then a roll motion and a pitch motion are generated. In the present embodiment, the roll attitude target control amount is calculated using the steering torque calculated by the driver steering, which is faster than the roll-related value and the pitch-related value representing the vehicle behavior. Therefore, compared to the case where the roll attitude is controlled according to the roll-related value or the pitch-related value representing the vehicle behavior, it is faster, specifically, almost at the same time when the input of the steering torque starts to be reflected in the vehicle behavior. , It is possible to reflect the control that enhances the driver's turning sensation. As described above, in the present embodiment, the roll and pitch of the vehicle can be synchronized by controlling the suspension, and the sense of unity with the driver can be enhanced.

[Embodiment 2]
Other embodiments of the present invention will be described below. For convenience of explanation, the same reference numerals will be added to the members having the same functions as the members described in the above embodiment, and the description will not be repeated.

This embodiment is different from the first embodiment in that the target pitch angle calculation unit 991 is provided instead of the target pitch angle calculation unit 891. FIG. 8 is a block diagram showing an example of the functional configuration of the target pitch angle calculation unit 991 according to the present embodiment. The target pitch angle calculation unit 991 includes a gain multiplication unit 95 instead of the gain multiplication unit 92. Further, the target pitch angle calculation unit 991 further includes a gain setting unit 96. In these respects, the target pitch angle calculation unit 991 is different from the target pitch angle calculation unit 891 in the first embodiment. The gain multiplication unit 92 and the gain setting unit 96 constitute a gain changing unit.

The gain setting unit 96 sets the gain value with reference to the lateral G signal indicating the lateral acceleration of the vehicle 900 and the front-rear G signal indicating the front-rear acceleration of the vehicle 900. The gain multiplication unit 95 refers to the gain value set by the gain setting unit 96, and changes the gain to be multiplied according to the gain value. Then, the gain multiplication unit 95 calculates the target pitch angle by multiplying the absolute value of the roll angle calculated by the absolute value calculation unit 91 by the changed gain.

When there is unevenness on the road surface, the unevenness causes the lateral G and the front-rear G of the vehicle 900 to fluctuate directly or indirectly via steering torque or the like. Therefore, it is advantageous to refer to the lateral G and the front-rear G of the vehicle 900 for calculating the target pitch angle from the viewpoint of performing suspension control that appropriately reflects the road surface condition.

[Embodiment 3]
Other embodiments of the present invention will be described below. For convenience of explanation, the same reference numerals will be added to the members having the same functions as the members described in the above embodiment, and the description will not be repeated.

In the present embodiment, the roll posture control unit 682 includes a steering torque target control amount calculation unit 84, a steering torque speed calculation unit 85, a steering torque speed target control amount calculation unit 86, and a steering torque-derived target control amount selection unit 87. However, it is the same as the above-described first embodiment except that the target control amount calculation unit 894 in the roll posture target control amount calculation unit 89 is configured to refer to the steering torque signal. FIG. 9 is a block diagram showing an example of the functional configuration of the roll posture target control amount calculation unit according to the third embodiment of the present invention.

The target control amount calculation unit 894 refers to the target control amount derived from the roll posture and the pitch moment, and also refers to the steering torque signal. For example, the target control amount calculation unit 894 calculates the first target control amount with reference to the roll posture-derived target control amount and the pitch moment. Then, the target control amount calculation unit 894 refers to the steering torque signal, corrects the first target control amount, and calculates the second target control amount. Then, the target control amount calculation unit 894 outputs the calculated second target control amount as the roll posture target control amount.

The correction of the target control value with reference to the steering torque signal is performed, for example, as follows. The target control amount calculation unit 894 sets the gain value with reference to the steering torque signal. For example, if the value of the steering torque signal (for example, the amount of displacement per unit time) is large, the gain value is also increased accordingly. The target control amount calculation unit 894 changes the gain to be multiplied according to the gain value, and multiplies the changed gain by the first target control amount to calculate the second target control amount. The gain may be multiplied by the roll posture-derived target control amount before the first target control amount is calculated, may be multiplied by the pitch moment, or may be multiplied by both of them.

Alternatively, in the present embodiment, the threshold value of the steering torque signal may be set. For example, the target control amount calculation unit 894 may perform a process of adding a pitch moment to the target control amount derived from the roll posture when the steering torque signal exceeds the threshold value, or the gain corresponding to the above steering torque signal. You may perform the process of multiplying by.

According to this embodiment, it is possible to execute the steering torque reference control according to the steering operation by the driver. For example, it is possible to execute steering torque reference control more strongly for a stronger steering operation. Therefore, it is even more effective from the viewpoint of providing the driver with a sense of unity with the vehicle 900 that matches the driver's turning sensation.

In the present embodiment, in addition to the reference of the steering torque signal, other state quantities of the vehicle 900 may be further referred to. For example, in the present embodiment, in addition to the steering torque signal, the lateral G signal and the front / rear G signal of the vehicle 900 may be further referred to. The lateral G signal and the front-rear G signal may be referred to in the calculation of the first target control amount or the second target control amount in the same manner as in the second embodiment described above. By further referring to such other state quantities, the effects of the above-mentioned second embodiment can be further expressed in addition to the above-mentioned effects of the present embodiment.

[Example of realization by software]
The control block of the vehicle 900 (for example, the roll attitude target control amount calculation unit 89) may be realized by a logic circuit (hardware) formed in an integrated circuit (IC chip) or the like, or may be realized by software. ..

In the latter case, the vehicle 900 includes a computer that executes the instructions of a program that is software that realizes each function. The computer includes, for example, one or more processors and a computer-readable recording medium that stores the program. Then, in the computer, the processor reads the program from the recording medium and executes it, thereby achieving the object of the present invention.

As the processor, for example, a CPU (Central Processing Unit) can be used. As the recording medium, in addition to a "non-temporary tangible medium" such as a ROM (Read Only Memory), a tape, a disk, a card, a semiconductor memory, a programmable logic circuit, or the like can be used. Further, a RAM (Random Access Memory) or the like for expanding the above program may be further provided.

Further, the program may be supplied to the computer via any transmission medium (communication network, broadcast wave, etc.) capable of transmitting the program. It should be noted that one aspect of the present invention can also be realized in the form of a data signal embedded in a carrier wave, in which the program is embodied by electronic transmission.

[Additional notes]
The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Is also included in the technical scope of the present invention.

For example, in the above-described embodiment, the threshold value of the steering torque signal may be set when referring to the steering torque signal. For example, a steering torque signal generated with an arbitrary movement amount larger than the play set in the steering member 410 may be used as a threshold value. According to this configuration, since the control of the present embodiment is performed when the driver substantially steers the steering member 410, it is possible to suppress the occurrence of excessive control in the present embodiment.

Further, in the above-described embodiment, the ECU 600 may be configured to select a specific target control amount as the roll posture-derived target control amount according to the type of the state amount of the vehicle 900 to be acquired. For example, when the ECU 600 receives the steering torque signal, the roll posture-derived target control amount selection unit 88 selects the steering torque-derived target control amount as the roll posture-derived target control amount with reference to the steering torque signal. can do.

As an example, in general, depending on the road surface condition, a more comfortable ride may be realized by outputting the target control amount derived from the steering angle signal without outputting the target control amount derived from the steering torque signal. is there. By adopting a configuration in which a specific target control amount is selected as the target control amount derived from the roll posture according to the type of state amount of the vehicle 900 to be acquired, a more suitable target is selected according to the road surface condition and the driver's intention. The control amount can be output. Therefore, according to this configuration, a more comfortable ride can be realized.

In the above-described embodiment, the control for enhancing the turning sensation is not limited to the control for reducing the difference between the phase of the roll angle and the phase of the pitch angle. For example, in addition to the phase difference, it is known that the driver's turning sensation is enhanced by appropriately controlling the relationship between the roll angle and the pitch angle. In the above-described embodiment, the roll posture target control amount may be calculated so as to have such a relationship between the roll angle and the pitch angle.

For example, it is known that the driver's turning sensation is improved by setting the amount of inclination of the vehicle in the front-rear direction during rolling to be lowered forward regardless of the turning acceleration. The relationship between the roll angle and the pitch angle in this case is expressed by the following equation. In the equation, θ is the pitch angle and φ is the roll angle. Further, in the following equation, the pitch angle falling forward is positive.

Further, it is known that the turning sensation is improved when there is always no phase difference between the roll angle and the pitch angle of the vehicle during rolling. In this case, the roll angle and the pitch angle are considered to have a proportional relationship and are expressed by the following equation. In the equation, k _rp is a constant of proportionality.

Further, it is known that when the ratio of the roll angular velocity and the pitch angular velocity is constant, the turning feeling is improved. In this case, it is expressed by the following formula. In the equation, the θ dot represents the pitch angular velocity and the φ dot represents the roll angular velocity.

Further, in the above-described embodiment, the roll posture target control amount calculation unit 89 does not refer to the actual pitch angle, but refers to the target pitch angle and roll angle calculated by the target pitch angle calculation unit 891 to refer to the roll posture target control amount. May be calculated. According to this configuration, it is possible to further reduce the control load for calculating the roll posture target control amount.

In the above-described embodiment, the state quantity of the vehicle 900 may be a measured value (measured value) by various sensors or an estimated value.

Further, in the above-described embodiment, other controls for enhancing the driver's turning sensation may be performed in parallel within the range in which the effect of the present embodiment can be obtained. For example, in order to optimize the phase of the combined motion of the roll motion and the pitch motion, when the vehicle 900 rolls, the difference between the damping force on the extension side and the damping force on the contraction side in the front wheel side absorber is increased. A control that is larger than the difference between the damping force on the extension side and the damping force on the contraction side in the rear wheel side absorber may be further added to the suspension control described above.

Further, in the above-described second embodiment, the gain changing unit may use one or both of the lateral G and the front and rear G. Further, the gain value may be set based on a state quantity other than the lateral G and the front and rear G.

Alternatively, in the above-described second embodiment, specific control according to the state of the vehicle 900 may be performed in parallel within the range in which the effect of the present embodiment can be obtained. For example, suspension stroke speed in a motion region where comfort regarding roll during steering is important, for example, in a motion region where lateral acceleration is within a predetermined range including 0.2 G (G represents gravitational acceleration) or 0.2 G. The damping coefficient of the front wheel side absorber and the rear wheel side absorber may be linearly increased from the contraction side to the extension side. Alternatively, the linear increase may be approximated to a stepwise increase to increase the damping coefficient in the motion region.

[Summary]
The suspension control device according to the embodiment of the present invention controls the damping force of the suspension. The suspension control device steers the target pitch angle calculation unit (891) that calculates the target pitch angle with reference to the roll angle signal, and the roll attitude target control amount that is referred to when controlling the damping force of the suspension. It includes a target control amount calculation unit (for example, a target control amount calculation unit 894) that calculates by referring to the torque signal and the target pitch angle. According to this configuration, it is possible to control the suspension capable of synchronizing the roll and pitch of the vehicle. Therefore, according to the above configuration, it is possible to enhance the sense of unity with the vehicle that the driver feels.

The target control amount calculation unit may calculate the roll attitude target control amount by referring to the steering torque-derived target control amount obtained by referring to the steering torque signal and the target pitch angle. According to this configuration, the reference of the steering torque signal when calculating the steering torque-derived target control amount, which is the roll posture-derived target control amount, is applied instead of the reference of the steering torque signal when calculating the roll attitude target control amount. This can prevent duplication of processing related to reference to the steering torque signal. Therefore, this configuration is even more effective from the viewpoint of performing suspension control that responds swiftly to changes in steering conditions.

The target control amount calculation unit may calculate the target control amount by further referring to the actual pitch angle. According to this configuration, it is possible to calculate the roll posture target control amount according to the pitch angle of the target pitch angle that does not overlap with the actual pitch angle. Therefore, the above configuration is more effective from the viewpoint of improving the accuracy of controlling the damping force of the suspension for enhancing the driver's turning sensation. Further, the target control amount calculation unit may calculate the target control amount according to the difference between the target pitch angle and the actual pitch angle. This configuration is even more effective from the above viewpoint.

The target pitch angle calculation unit may include a gain multiplication unit that calculates the target pitch angle by multiplying the roll angle signal by a gain. According to this configuration, the target pitch angle can be easily calculated by using the relationship between the roll angle and the pitch angle, which is more effective from the viewpoint of suppressing an increase in the control load.

The target pitch angle calculation unit may include a first gain changing unit that changes the gain value with reference to the lateral acceleration. Further, the target pitch angle calculation unit may include a second gain change unit that changes the gain value with reference to the front-rear acceleration. These configurations are even more effective in controlling the suspension from the viewpoint of appropriately reflecting the road surface condition.

The suspension device according to the embodiment of the present invention includes a suspension (suspension device 100) and a control unit (ECU 600) that controls the damping force of the suspension. Then, the control unit sets the target pitch angle calculation unit that calculates the target pitch angle by referring to the roll angle signal, and the steering torque signal and the target control amount that is referred to when controlling the damping force of the suspension. It is provided with a target control amount calculation unit that calculates with reference to the target pitch angle. According to this configuration, it is possible to control the suspension capable of synchronizing the roll and pitch of the vehicle, and thus it is possible to enhance the sense of unity with the vehicle that the driver feels.

81 Steering angle target control amount calculation unit 82 Steering angle speed target control amount calculation unit 83 Roll rate target control amount calculation unit 84 Steering torque target control amount calculation unit 85 Steering torque speed calculation unit 86 Steering torque speed target control amount calculation unit 87 Steering Torque-derived target control amount selection unit 88 Roll attitude-derived target control amount selection unit 89 Roll attitude target control amount calculation unit 91 Absolute value calculation unit 92, 95 Gain multiplication unit 96 Gain setting unit 100 Suspension device 105 Solvent valve 200 Body 300, 300A , 300B, 300C, 300D Wheels 310, 310A, 310B, 310C, 310D Tires 320, 320A Wheel speed sensor 330 Lateral G sensor 340 Front and rear G sensor 350 Yaw rate sensor 370 CAN
410 Steering member 420 Steering shaft 430 Torque sensor 440 Steering angle sensor 460 Torque application part 470 Rack and pinion mechanism 480 Rack shaft 500 Engine 510 Engine torque sensor 520 Engine rotation speed sensor 530 Brake pressure sensor 600 ECU
650 Suspension control unit 660 CAN input unit 670 Vehicle condition estimation unit 671 Steering correction amount calculation unit 673 Roll rate calculation unit 674 State estimation single-wheel model application unit 680 Ride comfort control unit 681 Skyhook control unit 682 Roll attitude control unit 683 Pitch attitude control unit 684 Unsprung control unit 690 Control amount selection unit 700 Power generator 800 Battery 891, 991 Target pitch angle calculation unit 892 Subtraction unit 893 Pitch moment calculation unit 894 Target control amount calculation unit 900 Vehicle

Claims (7)

A suspension control device that controls the damping force of the suspension.
The target pitch angle calculation unit that calculates the target pitch angle with reference to the roll angle signal,
The target control amount referred to when controlling the damping force of the suspension is calculated according to the difference between the target control amount derived from the steering torque obtained by referring to the steering torque signal and the target pitch angle and the actual pitch angle. The target control amount calculation unit that calculates by adding the pitch moments
Suspension control device equipped with. The suspension control device according to claim 1 , wherein the target control amount calculation unit further refers to the actual pitch angle to calculate the target control amount. The suspension control device according to claim 2 , wherein the target control amount calculation unit calculates the target control amount according to the difference between the target pitch angle and the actual pitch angle. The target pitch angle calculation unit is
The suspension control device according to any one of claims 1 to 3 , further comprising a gain multiplying unit that calculates the target pitch angle by multiplying the roll angle signal by a gain. The target pitch angle calculation unit
The suspension control device according to claim 4 , further comprising a first gain changing unit that changes the value of the gain with reference to the lateral acceleration. The target pitch angle calculation unit
The suspension control device according to claim 4 or 5 , further comprising a second gain changing unit that changes the value of the gain with reference to the front-rear acceleration. A suspension device including a suspension and a control unit that controls the damping force of the suspension.
The control unit
The target pitch angle calculation unit that calculates the target pitch angle with reference to the roll angle signal,
The target control amount referred to when controlling the damping force of the suspension is calculated according to the difference between the target control amount derived from the steering torque obtained by referring to the steering torque signal and the target pitch angle and the actual pitch angle. The target control amount calculation unit that calculates by adding the pitch moments
Suspension device equipped with.

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